1. Field
One embodiment of the invention relates to an acoustic apparatus and a method of controlling an acoustic apparatus.
2. Description of the Related Art
While listening to music through an earphone or a headphone (hereinafter, generally called “earphone”), a person may hear unnatural sound when the ear canal is plugged with the earphone, causing resonance between the eardrums and the earphone. It is therefore desired to measure the resonance characteristics of the ear canal and to correct the resonance characteristics before a sound-source signal is supplied to the earphone.
The shapes and acoustic transmission characteristic of ear canal, and the physical properties and acoustic transmission characteristic of eardrums differ from person to person. Further, the resonance in either ear canal changes in accordance with the type of the earphone and the state in which the earphone is held in the ear canal. Hence, the resonance characteristics of the ear canal of each listener must be corrected in order to achieve accurate correction of the resonance in the ear canal.
Jpn. Pat. Appln. KOKAI Publication No. 9-187093 discloses an acoustic playback apparatus (see paragraphs [0034], [0035] and [0036]). In this apparatus, a headphone having a unit composed of a speaker and a microphone generates and collects an audio signal sound, and the resonance frequency of the user's ear is measured. Based on the resonance frequency measured, the output level of the component of the audio signal that has the resonance frequency is lowered to a predetermined level.
The acoustic playback apparatus disclosed in the above-identified publication necessitates use of a headphone (earphone) having a unit composed of a speaker and a microphone. Inevitably, the headphone may be not only large, but also complex in structure. Further, the manufacturing cost of the headphone is high because the earphone includes a microphone. Still further, the timing of acquiring a response signal to the audio signal sound generated must be more accurately controlled than otherwise.